WD40

WD-40 is a brand name for a widely used spray that functions as a penetrating oil and moisture-displacing spray. It is marketed as a multi-use product for lubrication, rust prevention, and water displacement. The exact formulation is proprietary and not disclosed.

The product was developed in 1953 by the Rocket Chemical Company to prevent corrosion on missiles. WD-40 stands for Water Displacement, 40th formula attempted. The product gained broad popularity for general maintenance and is now produced by the WD-40 Company.

Composition and mechanism are not fully disclosed by the manufacturer, but the formula typically contains light hydrocarbons, mineral oil, and other solvents. These ingredients help displace water from metal surfaces and leave a temporary lubricating film. The product can penetrate rust and loosen seized components, though it is not designed as a heavy-duty lubricant for bearings or high-load equipment.

Common uses include treating tools, hinges, bolts, bike chains, and automotive parts. It can degrade certain plastics, rubbers, or paints, and may leave a film that attracts dust. It is not recommended as a long-term lubricant in high-temperature or high-load applications, and it should be avoided on sensitive electronics unless an appropriate cleaner is used.

Safety considerations include its flammability and the need to use it in well-ventilated areas, away from heat and open flames. It is widely available in hardware stores and online. The WD-40 Company also markets specialized products under the WD-40 Specialist line, including variants for specific tasks such as electrical contact cleaning and long-lasting lubrication.